This invention relates to a propeller driving device for a marine propulsion unit and more particularly to an improved bearing supporting arrangement for the propulsion shaft of a marine propulsion unit.
As is well known, many types of outboard drive units employ a lower unit in which a forward, neutral, reverse transmission is positioned for driving a propeller shaft to propel an associated watercraft. Normally, the propeller shaft is mounted within a cavity formed in the lower unit casing and is supported by means of a bearing carrier that is inserted into the rear end of this opening and is held in place by fastening devices. Normally, these fastening devices include bolts or studs and nuts with the heads exposed so as to facilitate insertion and removal. However, the exposed heads of the fasteners can give rise to turbulence that will decrease the efficiency of the propulsion unit. Furthermore, the exposed fasteners can also be damaged and give rise to difficulties in disassembly.
It is, therefore, a principal object of this invention to provide an improved arrangement for supporting a propulsion shaft of an outboard drive.
It is a further object of this invention to provide a fastening arrangement for a propeller shaft support wherein the fasteners do not interfere with the water stream and also will be protected from damage.
In connection with the fastening of the bearing carrier to the outer housing, the dissimilarity of metals used between the outer housing and the fasteners can give rise to corrosion problems. If corrosion occurs, it may be very difficult to disassemble the components for servicing.
It is, therefore, a still further object of this invention to provide an improved fastening arrangement wherein corrosion will be minimized and disassembly facilitated.